Where, by the way, I offer, whether galls (ſuppoſing all aſtringents work by twiſting and curling, as before I ſhewed) do not twiſt the aculeate particles of diſſolved copperas, making of themſelves no colour, into numerous cones, and thereby produce a black colour; the propriety of cones, and pyramids, and other acuminate bodies, being to return none of the light they receive, which is the ſame, as to cauſe inconſpicuity or blackneſs.
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